This project is a natural extension of a common interest of the Buc and Brenowitz laboratories in understanding how specific interactions are established between RNA and DNA polymerases and their binding sites on nucleic acids. To accomplish this, information from the three dimensional structures of the functional complexes is being combined with detailed kinetic analysis in order to characterize in real time the formation of macromolecular contacts seen in the structure. Dr. Buc[unreadable]s research group has expertise in enzymology, rapid kinetics, photo-crosslinking and radiolytic techniques. They have conducted extensive studies of polymerase-nucleic acid interactions using Escherichia coli RNA polymerase as a model system including studies of the gal promoter controlling the operon for galactose metabolism. The Brenowitz laboratory has a long-standing interest in the interaction of regulatory proteins with RNA polymerase Hat the gal promoter. The faithful transcription of nucleic acids Hwithin the appropriate temporal frame is a key component of cellular Hfunction and development as well as viral function and replication. HThe function of polymerases can be roughly divided into two Hcomponents, binding to a specific site on the template nucleic acid Hand the subsequent synthesis of a transcript. This collaborative Hproject focuses upon the mechanism of the first process.